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heat cracking windows
Does anybody know why when heat is applied to glass (like when removing vinyls from window) the glass always gives at the bottom, or has anybody had a crack appear any-wear other than bottom of pain (?)
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8 Replies
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If its heat related it will crack at the corners and head towards the other corner. Or if the glass has not been cut correctly and has a slight crack it will follow that. If its cold we will heat the windows.
But if you are going to do that be very carefully its a skill in it self to heat the window but also you have to let it cool down slowly or else it cracks.
Laminated windows are the worst as the plastic which is wedge between the two sheets expand and cause the glass to crack.
Ever since iv started heating windows iv only cracked one (left the heat gun on it) and i frost about 2/3 sites a week.
James
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quote James Langton:If its heat related it will crack at the corners and head towards the other corner. Or if the glass has not been cut correctly and has a slight crack it will follow that. If its cold we will heat the windows.But if you are going to do that be very carefully its a skill in it self to heat the window but also you have to let it cool down slowly or else it cracks.
Laminated windows are the worst as the plastic which is wedge between the two sheets expand and cause the glass to crack.
Ever since iv started heating windows iv only cracked one (left the heat gun on it) and i frost about 2/3 sites a week.
James
i was wondering if it could be due to pressure with the weight of the glass above pressing down
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the reason i put this thread on is i have had it happen to me but also know quite a few people say it as happened to them. in all cases it seems the crack started at the bottom. i have not heard anybody say the glass cracked any wear but at the bottom
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Umm unlikely. It depends how big the sheet is. If its toughed, safety etc.
Problem with glass is there are so many variables. Iv worked on some historic sites where the glass is as thin as paper and is so weak that you have to be careful when squeegeeing it. -
quote James Langton:Umm unlikely. It depends how big the sheet is. If its toughed, safety etc.
Problem with glass is there are so many variables. Iv worked on some historic sites where the glass is as thin as paper and is so weak that you have to be careful when squeegeeing it.have you ever heard of anyone saying the glass cracked some wear other than the bottom of the pane
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Misting it with soapy water & then using a sharp window scraper is by far the best, safest & fastest way to remove it and leaves no residue either.
If it’s cracking due to the heat and / or the stress of the vinyl being pulled off it’s probably FAR too hot / localised heat (only needs to be around 30 or 40 degrees to peel well.
In future never ever heat glass unless it’s tempered or toughened as it’s about the only glass that can stand up to some abuse….will also save you from possible replacement costs from irate owners.
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quote David Rogers:Misting it with soapy water & then using a sharp window scraper is by far the best, safest & fastest way to remove it and leaves no residue either.
If it’s cracking due to the heat and / or the stress of the vinyl being pulled off it’s probably FAR too hot / localised heat (only needs to be around 30 or 40 degrees to peel well.
In future never ever heat glass unless it’s tempered or toughened as it’s about the only glass that can stand up to some abuse….will also save you from possible replacement costs from irate owners.
Thanks David how would you go about removing from glass with bomb proof on i may have a bit of work like that comming in
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Glass tends to crack from the bottom centre (but not always) cos that is where most of the weight is upon it + uneven putty support + where it is held unmovable the most.
Glass will expand if heated uniformally but if heat is applied locally then it will not conduct throughout and cracking will occur.Ian :lol1:
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